Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G11/00—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers
  • G01G11/04—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having electrical weight-sensitive devices
  • G01G11/043—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having electrical weight-sensitive devices combined with totalising or integrating devices
  • G01G11/046—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having electrical weight-sensitive devices combined with totalising or integrating devices involving digital counting

Definitions

• the invention relates to a method and apparatus for weighmg by conveyor-type weighing unit, where a conveyor belt forming an endless loop is transported along a first guiding unit, defining a first conveying direction and extending in-between the top sides of a opposite arranged rollers.
• the belt is driving in a revolving manner by a driving unit and transported over a weighing device in a downstream direction.
• the weighing device being a part of the first guiding unit and perform weighing of objects transported along the conveyor.
• the object of the invention is to provide accurate and high-speed conveyor- type weighing unit capable of weighing objects of varying dimension at high- speed and operating performance.
• the conveyor-type-weighing unit is characterised in; the weighing device comprising; two or more side by side, in said conveying direction arranged weighing platforms, each platform having a pre-defined platform length, each weighing platform continuously weighing the conveyor belt section placed there over and/ or the object transported there on, one, two or more adjacent arranged weighing platforms constitutes at each time a weighing unit having a total platform length equal or greater than the object length to be weighed, said weighing platforms being operatively connected to a data processing unit, said data processing unit receiving and processing data from said weighing platforms, and based thereupon, the length/ weight of the object is determined and accordingly appropriate number of adjacent platform selected, having total length at least equal or greater than the object to be weighed and thereby enabling minimal spacing between adjacent objects and maximum operational capacity.
• the invention is moreover characterised in that the a predetermined limits, is when the first derivative of two successive measurements equals to zero.
• the invention is further characterised in that the number of weighing platforms is three or more. Moreover according to the invention it is particularly preferred that the platforms have different length.
• the number of platforms is unlimited.
• the number of platforms is unlimited and two or more of the platforms form a weighing unit which added platform length is larger than the length of the object to be weighed
• the method is characterised in that the object is moved along the conveyor belt in a downstream direction over a weighing device comprising two or more weighing platforms.
• the platforms are arranged side by side in the downstream direction.
• Each of the platforms continuously measure the weight of the conveyor belt transported over them.
• the weighing measurements are continuously sent to a data processing unit, where the measurements from one or more platforms are processed and continuously compared. If a certain number of repeated measurements from the platforms forms a weighing measurements within a prescribed minimum time- and/ or weighing range, such measurement represent the weighing of the respective object.
• the prescribed time- and/ or weighing minimum is when the first derivative ( ⁇ y/ ⁇ x) of two or more repeated weighing measurements equal to zero, then such measurement constitute the weighing of the object.
• the prescribed time and/ or weighing minimum is when the first derivative ( ⁇ y/ ⁇ x) of the added weighing of two or more weighing platforms equal to zero, then such measurement constitute the weighing of the object.
• Fig. la shows a diagram for the weighing capacity of a conveyor weighing unit with one platform of varying length
• Fig. lb shows a diagram for the weighing capacity of a conveyor weighing unit with three platforms of different length
• Fig. 2a shows a perspective view of the conveyor-type weighing unit according to the invention
• Fig. 2b is a side view of the conveyor-type weighing unit
• Fig. 3 is a sectional cut view of the conveyor belt and a weighing platform of the weighing device seen from the side,
• Fig. 4 is a front view of the conveyor-type weighing unit seen from the in-feed end
• Fig. 5 is a side view of one possible design of the conveyor belt with three weighing device of different length
• Figure 6 is a side view of a possible line up of three weighing platforms.
• Figure 7 shows a weighing diagram for the weighing of individual objects using three platforms
• the apparatus illustrated in the figure 2 - 6 comprises a conveyor-type weighing unit (2) arranged on a stationary supporting frame structure (41).
• a conveyor belt (3) being a part of the conveyor- type weighing unit forms an endless loop driven in a revolving manner by a driving unit (6).
• the conveyor belt is transported along a first guiding unit (15) arranged horizontally in direction extending downstream in-between to top sides of reversing rollers (16, 17).
• a weighing device (4) is incorporated as a part of the first guiding unit and thereby forming a part of a platform the conveyor belt is transported along.
• As the belt is transported along the first guiding unit (15) continuous weighing measurement are made by the weighing device.
• the section of the belt (Li) placed over the weighing platform (7) is weighed at each time.
• a computer data processing unit (10) is connected to respective parts of the equipment for monitoring and controlling the operation.
• Figure la shows a diagram for the weighing capacity of a conveyor weighing unit with one platform of varying length.
• the length of the weighing platform must be greater or equal the length of the object to be weighed. This is due to the fact that when the object is transported along the conveyor it is only when the whole object is placed on the weighing platform that a total weight can be measured. If the object is longer than the platform and rests on some other parts of the conveyor it is never possible to place the whole object on the platform and conduct weighing of the whole object. This results also in that the distance between two adjacent objects must be equal or greater than the length of the platform.
• the diagram shows how the number of weighing pr. minute (O s ) will be decreased if the length of the platform is increased. On the other hand one can se how the number of weighing can only be increased by decreasing the length of the platform. This however will result in that the weighing device will only be able to weigh shorter object. As the platform becomes shorter a greater number of objects will not be weighed.
• Figurer lb shows as figure la, the weighing capacity of a conveyor- weighing-unit, but now with three platforms each of different length.
• the number of weighing pr. minutes (O s ) is shown on the y-axis and the length of the platforms on the x-axis.
• the operational capacity is increased dramatically.
• the distance between adjacent objects are no longer determined by the platform long enough to weigh the longest object, but only by the length of the platform the next preceding object will be weighed on. If an object is weighed successively on the first platform, then the distance two adjacent objects on the conveyor is determined by the length of the first platform. If the object is successively weighed on the second platform, then the distance between that object and the next adjacent is determined by the length of the second platform, and so on.
• Figurer 2a shows a perspective view of the conveyor-type weighing-unit according to the invention.
• Figure 2b shows a side view of the same as fig 2a but where a side protecting plate (29) have been removed.
• a conveyor-type weighing unit (2) supported by a frame (41) is illustrated.
• the weighing unit (2) comprise a conveyor belt (3) forming a endless loop which is driven in a revolving manner by a driving unit (6) in a direction downstream (11) from an in-feed end (22) to an out- feed end (23).
• the driving unit (6) can be equipped with cogged driving wheel for interception with the belt and can be located anywhere along the conveyor path of the belt and either push or pull the belt over the horizontal first guiding unit.
• the belt (3) rests on a guiding unit (15) from a first- (16) to a second reversing roller (17).
• the rollers can be with or without sprockets for interception with conveyor belt or for example non-rotating round end-units which the belt slide over (as shown in fig 5) .
• a weighing device (4) forms a part of the guiding unit.
• a computer data processing unit (10) is connected to the weighing device (4) and other measuring unit of the apparatus.
• An object detector (19) is placed along the conveyor belt to detect objects to be weighed and transported along the belt. Further a belt placement detector (8) is arranged for example underneath the belt path to located a starting point (12) of the belt as the belt is transported along the first guiding unit.
• FIG. 3 shows a sectional view of the conveyor belt (3) and a weighing device (4) including a weighing platform (7).
• the conveyor belt (3) is moved in the downstream direction ( 1 1) over the weighing platform (7).
• the most preferable belt as shown on the figure is so called link-type belt.
• An unlimited number of links (27) are connected together by nit-type joint (26). Each link is turnable around the joints.
• almost any other type of belt can be used without foreseeable problems.
• Fig. 4 shows a front end view of the conveyor-type-weighing unit seen from the in-feed end (22).
• Fig. 5 is a sectional side view of one possible design of the conveyor belt guiding unit (15) with three weighing platform (7).
• the platforms are arranged one after the other in the conveying direction ( 1 1).
• the conveyor belt (3) runs over a first roller (16) defining the input end (22) of the first conveying direction ( 1 1).
• the belt runs further over the weighing platforms (7) being a part of the guiding unit (15) and then over the second roller (17) defining the output end (23) of the first horizontal conveying direction.
• the roller ( 16, 17) does not necessarily need to be rotable but can be curve or semi-circular on the end so the belt slides easily over them.
• the conveyor belt (3) is f.ex. driven by a toothed driving wheel (6) situated underneath the output end (23).
• FIG. 6 is a side view of a possible line up of three weighing platforms.
• the conveyor belt (3) is pushed or pulled over the guiding unit (15) in the first conveying direction ( 1 1) and over the weighing device (4), including the three weighing platforms (7) all being a part of the guiding unit for the conveyor belt.
• the sections (LA, LB and Lc) of the belt placed over the platforms are weighed.
• Figure 7 show a number of weighing diagrams for the weighing of individual objects transported along the conveyor belt and over the weighing platforms.
• the first of the diagrams shows three curves each representing the weighing of the platforms (A), (B) and (C).
• the length of the objects is 2 which is equal to the length of the first platform.
• the weighing on the first platform (A) shows a curve where the gradient of the curve is either larger or smaller than zero. In the maximum point, the gradient is equal to zero for one measurement.
• the weighing of the second platform (B) shows a curve where the gradient is equal to zero for a number of measurements, or for the time it takes the conveyor belt to move the object one unit length e.g. the platform length minus the object length.
• the weighing of the last platform (C) show a curve where the gradient of the curve is equal to zero for a larger number of measurements, and longer than for platform (B).
• the interval where the gradient is zero equals the time it takes the conveyor belt to travel with the whole object placed on the platform.
• both the curve for platform (A) and (B) show only one measurement where the gradient of the curve is zero. The curve does not get flat in the top section and therefor no valid measurements can be conducted.
• the curve shows one point where the gradient (dy/dx) is zero.
• the third platform (C) however show a curve where the gradient is zero for repeated number of measurements.
• the platform length is 5 but the object length (L) is still shorter than that or 3.
• a new curve is however shown. This is the combined, or added weighing of platform (A) and (B).
• the curve is plotted by dotted line and marked (A+B).
• the diagram therefor shows that as long as the objects is shorter than length of one, two or even the added length of all three of the platform accurate weighing measurements can be obtained.
• the diagram represent the weighing of a single object.
• the situation becomes more complex when a row of objects are transported over the weighing platforms. Then all of the platform can show weighings at the same time. Further two or more objects can be placed on one and the same platform at the same time.
• an object detector or sensor is placed in front of the first platform. The sensor will transmit information about that a new object is arriving to the data processing unit. By knowing the placement and time of arrival of the object onto the platform the data processing unit can organize and sort out the measurements from the platforms.
• the invention has been described with reference to a preferred embodiment. Many modifications can be carried out without thereby deviating from the scope of the invention.
• the length of the weighing platforms as well as the number of platforms can be varied in many ways without thereby deviating from the invention described herein.
• a number of measuring method can also be used to detect the object on the conveyor as well as detecting the starting point of the conveyor belt. By using taco-meter on the driving unit instead the belt detecting sensor one will obtain the same results.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Sorting Of Articles (AREA)
• Supplying Of Containers To The Packaging Station (AREA)
• External Artificial Organs (AREA)
• Telephone Function (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=36754841

Family Applications (1)

Country Status (6)

Families Citing this family (36)

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• 1999
  • 1999-01-20 AU AU25440/99A patent/AU2544099A/en not_active Abandoned
  • 1999-01-20 EP EP99905161A patent/EP1056991A1/de not_active Withdrawn
  • 1999-01-20 WO PCT/IS1999/000002 patent/WO1999036753A1/en not_active Application Discontinuation
  • 1999-01-20 US US09/600,645 patent/US6433288B1/en not_active Expired - Lifetime
• 2000
  • 2000-07-18 IS IS5564A patent/IS2768B/is unknown
  • 2000-07-20 NO NO20003724A patent/NO327400B1/no not_active IP Right Cessation

Non-Patent Citations (1)

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